1. Field of the Invention
The present invention relates to a photosensitive resin composition suitable for preparing a color filter used in a solid state color imaging device including a charge-coupled device (CCD), a bucket-brigade device (BBD) and a base store-type image sensor (BASIS), and in a contact type image sensor, a color display device, and the like. The present invention relates also to a method of manufacturing the color filter using the photosensitive resin composition.
2. Description of the Prior Art
In order to selectively radiate light of a specific wavelength on the surface of a solid-state imaging device such as a CCD, a color filter is formed thereon. The color filter is formed such that a photosensitive material is coated on a substrate, the coated photosensitive film is selectively exposed with light, the exposed film is developed, and the remaining pattern is dyed. The following materials have conventionally been used for forming such a color filter:
(a) a photosensitive composition wherein a dichromate as a photosensitizer is mixed in an animal protein such as gelatin, casein, or glue; and PA1 (b) a photosensitive composition wherein a dichromate or aromatic azide compound as a photosensitizer is mixed in a water-soluble polymer such as polyvinyl alcohol, polyacrylamide, or polyvinyl pyrrolidone. PA1 a photosensitizer comprising an aromatic azide compound.
The thickness and dyeing properties of a color filter having photosensitive composition (a) tend to vary since the animal protein in composition (a) is derived from a natural substance, and dark reactions are likely to occur. In addition, the dichromate may cause environmental pollution.
Photosensitive composition (b) has poor adhesion between the substrate and the photosensitive film formed therefrom. When the exposed film is developed, the film swells, thus resulting in degradation of resolution. Further, the composition cannot provide good heat-resistance or dyeing properties.
Japanese Patent Disclosure (Kokai) No. 59-155412 discloses a photosensitive resin composition obtained such that a water-soluble bisazide compound is mixed as a cross-linking agent with a terpolymer of N-vinyl-2-pyrrolidinone, a monomer having a quaternary ammonium structure and a polymerizable unsaturated bond, and an alkyl acrylate or an alkyl methacrylate. This composition has good dying properties but swells upon development. As a result, the resolution is degraded. In addition, a film of this composition has poor adhesion properties with respect to the substrate.